MTG

Commander players have a thing called "Rule 0" that basically says you can change whatever rules you want as long as your whole playgroup agrees to it. But if you want to get your changes accepted on a broader scale, so that you could go to a store event or a big tournament and expect other players to be familiar with them, that's a much taller hurdle. Can you convince the community that your banlist is better than the official one and also better than any other fan-made ones? Can you get stores to support it -- keeping in mind that they have to curry favor with Wizards in order to maintain WPN certification, be allowed to pre-order the amount of product they want, etc.? If you could do it successfully, you'd basically be building a grassroots competitor to the Commander Format Panel. Not impossible, but it would be an uphill battle for sure.